The present invention relates generally to fused wire terminations and more particularly to terminations in which a plurality of individually insulated wires or individually insulated wires of a stranded cable are fused within a tube-like terminal or device. The present invention also relates to the method of making such termination and the apparatus for making such termination.
Many attempts have been made to design methods and apparatus for quickly and reliably terminating a plurality of individually insulated wires to a terminal or other device. One standard technique today requires the insulation at the ends of stranded magnet wire, for example, to be manually or chemically stripped of insulation then placed in a partial ring-like device or terminal and crimped to a closed and compressed configuration.
A standard technique for terminating insulated transformer wire includes inserting them into a tube member that has a brazed longitudinal seam that serves to only hold the tube shape before compression. The tube has ridges or projections on its inner surface. The assembly is cold crimped causing the ridges to penetrate the wire insulation to make electrical contact with the outer surfaces of the wires therein.
These standard methods are not only time and labor consuming, but produce irregular or mechanically weak terminations which causes hot spots when the cable carries or the wires carry electrical power.
Methods of fusing an insulated wire to a terminal or other metal device are also known where the insulation is driven or burned away during the fusing process. See for example, U.S. patents: Riordan U.S. Pat. No. 5,111,015; Gibson, Jr. U.S. Pat. No. 3,519,778; Szantho et al U.S. Pat. No. 4,371,772.
Methods are also known for placing a number of wires in terminal or other device and fusing the assembly under heat and pressure to burn away or vaporize the insulation and fuse the parts together. See U.S. patents A. S. Warner U.S. Pat. No. 4,034,152 and Slavin et al U.S. Pat. No. 4,538,045.
A disclosure is also known purporting to include wrapping a metal wire mesh around three individually insulated rectangular conductors and inserting the assembly into a ring terminal and welding the assembly to burn off the insulation and enhance the electrical contact of the final product by the use of the wire mesh. See U.S. Pat. No 4,317,277.
Hand-held welding machines are also known that suspend from retracting winch mounted cables for movement in free space by an operator in order to be able to move the machine quickly from one welding location to another and to quickly change the welding head orientation. See ARO brand Spot Welding Guns Models N297A and B, ARO Machines A Souder, Chilly-Mazarin, France.
Notwithstanding prior methods and arrangements and apparatus, the need for faster and more reliable methods and equipment for making such terminations continues to grow. Some of the problems with prior systems include excessive manual and time consuming efforts, the inability of maintaining a proper fusing or welding head orientation manually just prior to fusing power application, inability to develop a reliable, reproducible, and uniform electrical connection among the fused and compressed assembly of parts, the need to introduce an element or filler material between the individual wires in order to adequately burn off insulation, the inability to fuse magnet wire cables without producing substantially low production yields, and the need to use chemicals or manual insulation stripping equipment and steps.